When I learned that the "swell" in the ADDAC508 Swell Physics had to do with the ocean, it piqued my interest. The ocean is one of my loves, and while I hadn't surfed since I moved from beautiful, amazing, sunny, southern Cal to equally beautiful and amazing (sunny sometimes) New Hampshire, the four months I spent living in a crappy apartment and doing nothing but drinking Bud Ice Light and surfing meant that I was, and am, a surfer for life, right? Therefore, anything surf related, from the latest neoprene technology to local weather reports, can make me giddy. I'm also a fan of theoretical models, especially when they pertain to what’s usurped surfing's space in my life—modular synths.
Swell Physics is a modulation source where the long and short of the theoretical situation is that there are four anchored buoys in the middle of the ocean and we can control various things to move the buoys around. These buoys have the ability to transmit their height to the module so that you can use the buoy changes as CV modulation in patch. Since these buoys don't exist in the real world and something needs to move them around, Swell Physics uses a Gerstner Wave (named for German-Bohemian scientist Franz Josef Gerstner) to create such movement. A Gerstner wave (also called a trochoidal wave) solves what might or might not be a theoretical approach to defining specific wave movements. Not being a scientist myself, when I looked up what a Gerstner wave is, I found definitions littered with terms, phrases, and syntax that I had no clue about. What I think I did understand was that using these waves for simulations was a good way to get lifelike wave movement to power our fictitious buoys, therefore moving our patches around.
What all of this science, theory, and wave simulation gives us is an interesting and, ahem—fluid—CV movement that is constantly changing shape, but in a way that the ocean would. Not quite predictive, but not exactly random, either. As somebody who has spent more time in the ocean bobbing up and down waiting for perfect waves than standing upright on a surfboard, I have a kinship, a true connection to this type of movement. It's calming, grounded…oceanic.
There are two modes (A/B) that exemplify this movement well, being different ways of computing a Gerstner waver. Mode A is a scrolling mode where all the buoys follow the same path, and Mode B is an evolving mode, well explained in the manual:

"Evolving is the normal computation for a Gerstner wave, at all steps all points in the wave are calculated according to the settings and the points close by which also affect each other in a symbiotic relationship resulting in different paths for all buoys which are more or less related according to the settings."

To control all the parameters and elements in Swell Physics that make up the movement, there are six elements with which we do this; Swell Size (the distance between the highest point of the wave and the lowest), Agitation (a combination of wind and auxiliary waves that interact with the main waves), Spread (how far apart the buoys are from each other, like a delay), Simulation Speed, and Offset and Output Gain for dialing in the desired CV range that spans 10V PTP. There's CV control over these parameters so we can add more complexity and also a couple of Gate Outputs; one that goes high for when buoy 1<2 and another when buoy 3>4, for some external quasi-random syncing. There are also four sixteen-bit CV outputs (1-4) for each buoy, and an Average output that averages those four. All that remains for the grand tour are a few toggle switches: A/B Mode, voltage range (+/-5V or 0-+10V), and a switch to choose the CV destination for the Offset and Gain (they share a CV input).
As a modulation source, having the four buoy outputs and the Average output was a nice way to get some slightly related CV in my patches where the four outputs seemed to have the same shape, but were out of phase with each other, related to the amount of Spread was happening. If the changes are static (i.e. a twisting of the knob), once a given parameter settles in, the results can be more predictable, but when CV is introduced to any of the parameters, it becomes much less so; very stormy. Patched to the WORNG Parallax filter cutoff with resonance high, and everything on Swell Physics at max gave me bubbling brook type sounds very much in keeping with the theme of the module.
Though the modulation provided by Swell Physics produced a lot of random sounding movement, once there was some Spread added in, and depending on what it was patched to, it did seem to sync up occasionally and there were related generative changes that kept things moving. Tuning four VCOs to an A, with two being 440Hz and one pitched an octave higher and another an octave lower, once I patched in the modulation from Swell Physics to the 1V/Oct input of each my starting point of all A's disintegrated, though depending on how fast I had each of the four main parameters on Swell Physics, all sorts of droning goodness was had. I really was trying to give sound to the movement of this theoretical ocean, not just using the ocean to give movement to sounds, and when everything was slow, it was easy to imagine this and hear the results. Likewise, when I did the opposite and sped everything up and made it bigger; it was the storm in the middle of nowhere where you might not make it out.
I really tried to keep this oceanic theme going, and so attempted to patch realistically into each CV input. Simulating what I imagined to be an annoying jet ski cruising by one of the buoys with a sawtooth wave, I modulated the output of that by patching into a VCA and using a buoy output for the CV in of said VCA to simulate the movement around a buoy by said annoying jet skier.
Multing and panning that sawtooth to control more outputs so that the jet ski would be bothering all four buoys, and the sound became more dynamic. With some quad action going on, situated in the middle of the four speakers (the outputs of the four buoys), you might even feel like you were in the middle of the ocean cursing that damn jet skier. It was a fun experiment, and very different from using four different random LFOs instead.
I was pretty happy with my simulated jet ski motor sound, and used this VCAd sawtooth for modulating the other parameters as well. The A/B mode switch was a nice way to change things up quickly, and the difference between the two is pronounced, though not necessarily easily described, as well as the mathematics making up each (as far as I could tell!).
I like these theoretical systems as they bring a different type of thinking to modular. It's fun to enter these types of spheres of theory to try to push it, to ponder like a philosopher. You know it's not real life, but the lack of realness doesn't mean that it doesn't translate to the real world. Just watch out for jet skis.

Price: $399

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